<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box {
            width:900px;
            margin: 100px auto;
        }
        .top ul{
            overflow: hidden;
        }
        .top ul li {
            float: left;
            list-style: none;
            margin-right: 20px;
        }
        .top ul li a {
            display: block;
            width: 100%;
            height: 100%;
        }
        .bottom {
            width: 860px;
            height: 550px;
            text-align: center;
            line-height: 550px;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="top">
            <ul>
                <li><a href="images/1.jpg">
                    <img src="images/1-small.jpg" alt="">
                </a></li>
                <li><a href="images/2.jpg">
                <img src="images/2-small.jpg" alt=""></a></li>
                <li><a href="images/3.jpg">
                <img src="images/3-small.jpg" alt=""></a></li>
                <li><a href="images/4.jpg">
                <img src="images/4-small.jpg" alt=""></a></li>
            </ul>
        </div>
        <div class="bottom">
            <img src="images/placeholder.png" alt="" width='400px' height='400px'>
        </div>
    </div>
    <script src='../jquery-1.12.4.js'></script>
    <script>
        $(function(){
            $('.top a').on('click',function(){
                $('.bottom img').attr('src',$(this).attr('href'))
                return false;
            })
        })
    </script>
</body>
</html>